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GI tract infection


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What are the normal host defenses for the GI tract?
-Stomach HCl
-Intestinal sIgA, peristalsis, normal flora, phagocytes.
What are the 3 main ways of acquiring bacterial enteritis?
1. Invasion of intestinal mucosa and organism proliferation
2. Colonization of GI tract then exotoxin production.
3. Ingestion of preformed exotoxin
What 7 organisms can invade the intestinal mucosa and proliferate?
What does less vey stand for?
Listeria, Enteropathic Ecoli,
Salmonella, Shigella
Vibrio parahemolyticus,
Yersinia enterocolitica
What does shigella cause?
Bacillary dysentary transmitted fecal to oral.
How is salmonella passed?
Which 2 of these organisms produces H2S?
How is Edwardsiella transmitted?
By fish and reptiles/aquariums.
How is Yersinia enterocolitica passed?
In undercooked milk and pork. May be in blood transfusion bags
Hey! what's EPEC?
Enteropathogenic E. coli - causes enteritis, but is less common than hemorrhagic.
what is vibrio parahemolyticus found in?
Shellfish and sea food in the far east.
What does Listeria monocytogenes like and is found in?
Cold - cheese, dairy, hot dogs.
What 8 pathogens colonize the intestinal tract then produce exotoxin?
1. Hemorrhagic Ecoli
2. Enterotoxigenic Ecoli (ETEC)
3. Vibrio cholerae
4. Campylobacter jejuni
5. Aeromonas and Plesiomonas
6. Clostridium perfringens
7. Clostridium difficile
8. Clostridium botulinium in honey for infants
Where is Hemorrhagic ecoli found?
Petting zoos, undercooked beef
What does Ecoli 0157 H7 cause in kids?
Hemolytic Uremic Syndrome HUS
How does ETEC differ from EPEC?
antigenically; enteropathogenic invades mucosa and proliferates; toxigenic colonizes and produces exotoxin.
-Via contaminated food/H2O
How is vibrio cholerae transmitted?
In water.
What is Campylobacter jejuni transmitted in?
How do Aeromonas/Plesiomonas diff from most GNB?
-How do they affect stools?
-How are they transmitted?
-They are oxidase positive
-Turn stools green/malodorous
-In contaminated water
Where is Clostridium perfringens found?
In cafeteria food
What is Clostridium difficile caused by?
-Antibiotic associated
-Suppression of normal flora
How must Clostridium diff. be tested for?
It CANNOT be cultured; must test for Toxins A and B in stools with EIA.
What causes infant botulism?
Honey - in infants under 6 mo b/c of lack of normal flora.
What 4 organisms cause enteritis from ingestion of preformed toxins?
1. Staph aureus - protein foods
2. Bacillus cereus - fried rice, meat sauces
3. Clostridium botulinum - canned foods.
What are the 2 broad types of peritonitis?
1. Primary - no known cause.
2. Secondary - obvious reason
What 4 organisms are found in Primary peritonitis in kids?
1. Strep pneumo
2. Strep A
3. Staph aureus
4. Enterobacteriaceae
What 3 organisms are found in Primary peritonitis in adults?
1. E. coli/other enterobacteria
2. Strep pneumo
3. Strep A
What 4 things cause secondary peritonitis?
1. Trauma - surgery, hernia, cancer, perforated bowel.
2. PID
3. Primary infection elsewhere
4. Peritoneal dialysis -CAPD
What does CAPD stand for?
Chronic ambulatory peritoneal dialysis - in end stage renal disease.
What are the 2 most common enterococci?
which is MORE common?
which is more antibiotic resist?
-Fecalis - 80-90%
-Faecium - 90% resist vancomycin
How do you seperate Enterococcus from streps?
-Bile esculin pos
-6.5% NaCL Pos (alternt is PYR)
How do you speciate enterococci?
With Carb fermentation - sorbitol and arabinose
What are the Sorbitol/Arabinose reactions for:
-E. facalis
-E. faecium
Facalis = Sorb + Ara -
Faecium = Sorb - Ara +
What is Mannitol salt or CNA for?
Staph aureus/gram pos cocci
What is BA used for when testing for ENTERIC organisms?
Better growth for oxidase test with fastidious organisms.
What is SMAC for?
Hemorrhagic E. coli
What is Skirrow media for?
What are the characteristics of campylobacter?
-Grows at 42'C for 48 hrs in microaerophilic environment.
-Curve GNB, Oxi +/Catalase +
-Darting umbrella motility
What is each for:
TCBS = Vibrio
CIN = YerCINia

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